Land subsidence, known to have occurred in many parts of Gulf Coast of the United States (GC) as a consequence of complex geological conditions, high-intensity resource exploitation and land use. This subsidence has caused extensive damage to buildings and other infrastructures. By exploiting 1650 images from 33 ALOS-1 paths during 2007–2011 using multi-temporal interferometric synthetic aperture (InSAR) techniques, we have constructed, for the first time, a deformation map over 500,000 km2 of the 1900-km-long GC, with an RMSE of <10 mm/yr. The GC is generally stable, but numerous land deformation zones have been discovered, including at least 30 subsidence patterns and 14 uplift features. The maximum rate of subsidence measured is about 56 mm/yr at Stratton Ridge Oil Field, Texas. Most of the identified ground instabilities are newly discovered as a result of this study. The land deformation along GC is caused by both regional geological conditions and human activities that have influenced natural surroundings and consequentially exacerbated ground instability. Depressurization of petroleum reservoirs and aquifer compaction related to groundwater withdrawal are the principal impactors on observed subsidence. Other processes, including wastewater injection, sulfur/salt mining, dewatering, oxidation, and construction work, also contributed to the InSAR-mapped ground instability. Our large-scale deformation mapping will help the scientific community and relevant agencies better understand land deformation rates and extents, identify the processes responsible for the coastal deformation, and provide a critical dataset for hazard prediction and mitigation in the GC.